fix open file limit exceeded

For blogs with more than 512 pages, the default open file limit for most
Kernels (1024) is exceeded. In this case the operating system just
refuses to open any more files.

Instead of using defer and wait for the files to be closed, run the
(*os.File).Close function after completing working with the file instead
of waiting for the function to return before closing the files.

Fixes: #11
Fixes: b60fc70 ("hello world")
Signed-off-by: Moritz Poldrack <[email protected]>

main.go

@@ -1,11 +1,9 @@
 package main
 
 import (
-	"bufio"
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io"
 	"log"
 	"net/url"
 	"os"
@@ -14,12 +12,10 @@ import (
 	"strings"
 
 	"github.com/fsnotify/fsnotify"
-	"github.com/russross/blackfriday"
 )
 
 // init runs before main()
 func init() {
-
 	// we are making a list of folders here to check for the presence of
 	// if they don't exist, we create them
 	foldersToCreate := []string{inFolder, outFolder, templateFolder, pluginsFolder}
@@ -28,11 +24,9 @@ func init() {
 		log.Println(createFoldersErr)
 	}
 	FindZips(pluginsFolder)
-
 }
 
 func main() {
-
 	// check to see if the user ran with --watch
 	watchFlag := flag.Bool("watch", false, "watch the current directory for changes")
 	flag.Parse()
@@ -58,13 +52,11 @@ func main() {
 	markdownToHTML(inFolder, outFolder, templateFolder)
 	createPostList(inFolder, outFolder, templateFolder)
 	createAboutPage(outFolder, templateFolder)
-
 }
 
 // recreateHeaderFooterFiles recreates the header and footer files
 // if we're rebuilding the templates, we'll need these.
 func recreateHeaderFooterFiles(templatesFolder string) error {
-
 	headerFile, err := os.Create(templatesFolder + "/header.html")
 	if err != nil {
 		return err
@@ -88,7 +80,6 @@ func recreateHeaderFooterFiles(templatesFolder string) error {
 }
 
 func watchFoldersForChanges(folders []string) {
-
 	// range through the watched files
 	for _, folder := range folders {
 
@@ -104,7 +95,6 @@ func watchFoldersForChanges(folders []string) {
 		// make a channel for goroutine messaging
 		done := make(chan bool)
 		go func() {
-
 			// for { ev ... ver }
 			for {
 				select {
@@ -136,9 +126,7 @@ func watchFoldersForChanges(folders []string) {
 
 // createFolders takes a list of folders and checks for them to exist, and creates them if they don't exist.
 func createFolders(folders []string) error {
-
 	for _, folder := range folders {
-
 		if _, err := os.Stat(folder); os.IsNotExist(err) {
 
 			err = os.MkdirAll(folder, os.ModePerm)
@@ -159,57 +147,8 @@ func createFolders(folders []string) error {
 	return nil
 }
 
-// markdownToHTML converts markdown documents to HTML
-func markdownToHTML(inFolder, outFolder, templateFolder string) {
-	files, _ := os.ReadDir(inFolder)
-
-	for _, file := range files {
-
-		// only markdown files
-		if filepath.Ext(file.Name()) == ".md" {
-
-			// open the selected markdown file
-			markdownFile, _ := os.Open(inFolder + "/" + file.Name())
-
-			// don't forget to close it when done
-			defer markdownFile.Close()
-
-			// create the html file
-			htmlFile, _ := os.Create(outFolder + "/" + file.Name() + ".html")
-			defer htmlFile.Close()
-
-			// read the md
-			reader := bufio.NewReader(markdownFile)
-			markdown, _ := io.ReadAll(reader)
-
-			// send the md to blackfriday
-			html := blackfriday.MarkdownCommon(markdown)
-
-			// read in our templates
-			header, _ := os.ReadFile(templateFolder + "/header.html")
-			footer, _ := os.ReadFile(templateFolder + "/footer.html")
-
-			// assemble in order
-			completeHTML := string(header) + strings.TrimSpace(string(html)) + string(footer)
-
-			// pass the assembled html into ScanForPluginCalls
-			htmlAfterPlugins, htmlAfterPluginsErr := ScanForPluginCalls(completeHTML)
-			if htmlAfterPluginsErr != nil {
-				log.Println("error inserting plugin content: ", htmlAfterPluginsErr)
-				log.Println("returning content without plugin...")
-
-				// if there's an error, let's just take the html from before the error and use that.
-				htmlAfterPlugins = completeHTML
-			}
-
-			fmt.Fprintln(htmlFile, htmlAfterPlugins)
-		}
-	}
-}
-
 // createPostList creates the page that has a list of all of your posts
 func createPostList(inFolder, outFolder, templateFolder string) {
-
 	// read the files in the directory
 	files, _ := os.ReadDir(inFolder)
 
@@ -225,7 +164,6 @@ func createPostList(inFolder, outFolder, templateFolder string) {
 
 	// for all files...
 	for _, file := range files {
-
 		// if it is a markdown file...
 		if filepath.Ext(file.Name()) == ".md" {
 
@@ -237,15 +175,12 @@ func createPostList(inFolder, outFolder, templateFolder string) {
 			postList += "<li><a href='" + url.PathEscape(file.Name()) + ".html'>" + title + "</a></li>"
 
 		}
-
 	}
 
 	// if there are more than 0 posts make an RSS feed
 	if len(files) > 0 {
-
 		// generate the rss feed
 		CreateXMLRSSFeed(inFolder, outFolder)
-
 	}
 
 	// end the list
@@ -266,7 +201,6 @@ func createPostList(inFolder, outFolder, templateFolder string) {
 }
 
 func createAboutPage(outFolder, templateFolder string) error {
-
 	// create the about file
 	aboutFile, err := os.Create(outFolder + "/about.html")
 	if err != nil {

markdownRender.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/russross/blackfriday"
+)
+
+// markdownToHTML converts markdown documents to HTML
+func markdownToHTML(inFolder, outFolder, templateFolder string) {
+	files, _ := os.ReadDir(inFolder)
+
+	for _, file := range files {
+		// only markdown files
+		if filepath.Ext(file.Name()) == ".md" {
+
+			// open the selected markdown file
+			markdownFile, _ := os.Open(inFolder + "/" + file.Name())
+
+			// create the html file
+			htmlFile, _ := os.Create(outFolder + "/" + file.Name() + ".html")
+
+			// read the md
+			reader := bufio.NewReader(markdownFile)
+			markdown, _ := io.ReadAll(reader)
+
+			// send the md to blackfriday
+			html := blackfriday.MarkdownCommon(markdown)
+
+			// read in our templates
+			header, _ := os.ReadFile(templateFolder + "/header.html")
+			footer, _ := os.ReadFile(templateFolder + "/footer.html")
+
+			// assemble in order
+			completeHTML := string(header) + strings.TrimSpace(string(html)) + string(footer)
+
+			// pass the assembled html into ScanForPluginCalls
+			htmlAfterPlugins, htmlAfterPluginsErr := ScanForPluginCalls(completeHTML)
+			if htmlAfterPluginsErr != nil {
+				log.Println("error inserting plugin content: ", htmlAfterPluginsErr)
+				log.Println("returning content without plugin...")
+
+				// if there's an error, let's just take the html from before the error and use that.
+				htmlAfterPlugins = completeHTML
+			}
+
+			// don't forget to close it when done
+			markdownFile.Close()
+			htmlFile.Close()
+
+			fmt.Fprintln(htmlFile, htmlAfterPlugins)
+		}
+	}
+}